On 22/Oct/16 23:59, Marian Ďurkovič wrote:
> > The question here is, whether MPLS is the *optimal* solution for campus needs. > > The same functionality could be obviously achived by multiple technologies, > and while MPLS is well supported on high-end SP routers, various limitations > appear when people try to use it on commodity ASICs which typically empower > today's ethernet switches - one of them being e.g. limited ability to > effectively load-balance traffic over multiple parallel links. > > Yes, in theory we could build all campus LANs using high-end SP routers, but > when 100GE backbone is desired (which is often the case in EDU/NREN sector), > the costs of such solution jump to unacceptable heights. > > Thus we looked for another technology, which doesn't have the usual L2 > problems > and is able to provide services we need (including L2 extensions to remote > campuses) at reasonable costs and with enough simplicity. > > To avoid typical L2 problems, you clearly need a solution based on L3 routing. > And TRILL is exactly that - although it maintains L2 interface to the outside > world, internally it performs dynamic L3 routing by IS-IS protocol with all > safety belts like TTL check, RPF check etc. > > IMHO, TRILL is much better fit for campus needs, since it was specifically > designed for this networking space - and our 6-months production fully > confirms > that view (of course, YMMV). I don't consider the ASR920 or CES2000 to be particularly high-end routers, but YMMV. True, merchant silicon presents a number of data plane challenges that may, at first, seem non-trivial or completely go unnoticed. That is why we stay away from the ACX5000, for example. I expect improvements to come with newer-generation ASIC's/NP's, but that tests one's patience. But, like I said, I have not run TRILL myself, so I'm not going to tell you that it's not an ideal technology for this use-case. All I'll say is that MPLS is not limited to high-end platforms, even when custom silicon is involved. Mark.